The invention relates generally to a process and arrangement for the enrichment of a gas containing at least two components so as to obtain a gas enriched in one of the components. More particularly, the invention relates to such a process and arrangement wherein one of the components is selectively adsorbed and subsequently desorbed to yield a gas enriched in the selectively adsorbed component. Of special interest is the oxygen-enrichment of air and similar gases by selective adsorption of the oxygen.
For recovering oxygen, there is today chiefly employed the distillation of liquid air. When it is necessary, in carrying out a process, to use a gas which, in contrast to air, has an oxygen concentration of 40-90% as, for instance, is the case in the newer procedures utilized by the iron working industry, it is customary to obtain such oxygen enriched air by mixing air with the correspondingly necessary amount of pure oxygen. It is also possible to obtain a gas of the desired oxygen content by distillation of liquid air. All of the aforesaid processes are, however, very expensive and can be made economically acceptable to industry only by continuous operation.
It has also already been proposed to recover oxygen enriched air utilizing an adsorption process employing siliceous or carbon-containing adsorption agents and involving the use of temperature or pressure changes during adsorption and desorption. Certain silicates, for example, zeolites, are effective for preferably adsorbing nitrogen from its mixtures with oxygen so that, by conducting air through a zeolite-filled adsorber, the first issuing gas is effectively enriched as regards its oxygen content. The regeneration of the zeolite, however, requires a considerable outlay for energy and apparatus. Additionally, the zeolites are completely effective only when used with dry air since they are hydrophilic.